When a user purchases a new disk drive for upgrading an existing system, such a disk drive is often much larger (as well as possibly faster) than the existing hard drive. One option that the user has is to replace the original drive with the new drive, after saving the data from the old drive and copying it to the new drive in some way. This is not particularly desirable, because the initial save and copy operation is required, and the original drive is then not used.
Another option that a user has is to add the new drive to the existing system (e.g., with existing drive C:\) under a new drive letter, (e.g., D:\). This is also not particularly desirable to many users that do not want multiple hard drive volumes, each with its own namespace, own free space, and so forth. A similar situation exists on operating systems (such a Unix systems) that mount volumes at directory such as /user/volume2. Although it is feasible for a file system volume to span multiple spindles using established volume manager techniques such as striping, spanning or concatenation, these techniques have a number of constraints for end users, including that they often require changes to the BIOS/kernel/volume manager to support proper booting, and the entire file system fails when any one disk fails or is removed. As can be appreciated, this solution is impractical with removable drives, which are becoming commonplace, since the disk set created via striping, spanning or concatenation cannot tolerate the removal of one of its elements, whereby the removable disk is effectively no longer removable.
In short, known techniques for increasing the amount of non-volatile storage on a computer system suffer from the above-identified problems and other drawbacks.